Dual container system and method of manufacturing the same

ABSTRACT

There is provided a container system adapted to withstand a single impact or repeated impacts. The container system possesses one uniform wall thickness throughout the entirety of its body so as to be impact-resistant. The container system features a first container having a first container body and a second container having a second container body. The second container defines a second body height and a second body wall thickness. A body recess adapted to releasably engage the first container body is formed on the second container body and is extended along the second body height. The body recess defines at least one recess bottom corner having a recess bottom corner wall thickness which is at least substantially similar to the second body wall thickness of the second container body. This specified bottom corner wall thickness of the body recess allows the second container to withstand the single impact or repeated impacts.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part application of pending U.S. patent application Ser. No. 10/614,438 entitled RECESS CONTAINER DISPENSER AND METHOD OF MAKING SAME and filed on Jul. 3, 2003, the entirety of which is expressly incorporated by reference herein.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

(Not Applicable).

BACKGROUND OF THE INVENTION

The present invention relates generally to dual container systems, and more particularly to an improved dual container system featuring an impact-resistant container which possesses one uniform wall thickness throughout the entirety of its body and provides a unique horizontal support for its counterpart container that engages therewith.

It is a common practice for manufacturers and/or retailers to employ the use of containers for packaging their products and making them available in the marketplace. These containers not only protect the products from contamination, but may further facilitate the use of the products. Indeed, the significance and importance of providing user-friendly containers are truly appreciated by various industries as they can increase the overall attractiveness and appeal of the products in the marketplace.

One notable type of user-friendly container currently in use is the dual container system which typically allows large and small containers to be cooperatively engaged with each other. Dual container systems offer the convenience and freedom of product mobility as the smaller container can always be disengaged from the larger container and accompany the consumer.

To illustrate this point by way of an example, the dual container system may be adapted for frequent traveling as the smaller container containing a product such as shampoo or soap may be taken along. This obviously eases the size of the load that the traveler has to carry. Of course, the larger container can be left behind and provide all the functions of a traditional container when the traveler returns home.

Although the current dual container systems may achieve their primary objective of product user-friendliness, they possess certain deficiencies which detract from their overall utility. Perhaps the greatest deficiency of the conventional dual container systems is the inability to withstand repeated or repetitive impacts originating from their environment. The dual container systems of the conventional art are frequently subjected to tear and/or rupture as many of them are repeatedly dropped and/or mishandled during their shipment and/or storage.

In particular, the recess of the larger container which is used for engaging the smaller container is vulnerable to tear and/or rupture as its edges forming the outer boundaries thereof are not sufficiently thickened. Even more vulnerable than the recess edges are the corners formed on the bottom portion of the recess. More particularly, these bottom corners of the recess are extremely thin compared to the other portions of the larger container. This is understood to be a result of a manufacturing deficiency in which insufficient amounts of preform materials are distributed to that region.

As such, while the rest of the larger container is uniformly thickened to a sufficient degree, it is often the case that the bottom corners of its recess fail to reach the same, or even similar, thickness. In this regard, the bottom recess corners are especially prone to being torn or ruptured. Obviously, this has the inevitable negative effect of spilling or discharging some, if not all, of the products contained within the larger container. The product loss resulting from such structural failure may become burdensome when translated into dollars and cents in loss profits.

In addition, it is often the case that vertical edges or corners at the intersections of the body recess with the larger container body sides are also extremely thin compared to the other portions of the larger container. Such thinned vertical corners are unfortunately prone to tearing or rupturing which has the negative effect of spilling or discharging product contained within the larger container.

Another significant deficiency that casts a shadow upon the dual container systems of the conventional art is the inability of the larger container to provide an adequate horizontal support for the smaller container. Although various container systems may provide certain individualistic mechanisms for engaging the smaller container, they all essentially follow the same guideline of trapping or capturing the smaller container within the recess through the use of a compressive force.

However, those mechanisms cannot account for certain situations such as the smaller container being inadvertently slipped out through the underside of the recess due to the force of gravity. This scenario is more likely to happen as the time goes on since the mechanisms for engaging the smaller container would eventually become weakened. As such, the risk of container slippage is a possibility which can detrimentally undermine the overall utility and value of the dual container system.

In view of the above-described shortcomings of the conventional dual container systems, there exists a clear need in the art for an improved dual container system which has a sufficient structural integrity to withstand a single significant impact and/or repeated impacts that are undesirably imposed thereon. Moreover, there exists a further need in the art for an improved dual container system that can provide an adequate horizontal support to its smaller container so as to prevent any inadvertent slippage from underneath the recess of the larger container.

BRIEF SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates the above-referenced deficiencies associated with the dual container systems of the prior art. More specifically, the present invention is an improved dual container system which is specially designed and manufactured to withstand a single impact or repeated impacts undesirably caused thereupon. This prevents the present container system from tearing or rupturing at any specific portions thereof so as to effectively contain any associated product (e.g., shampoo, body wash, candies, toys, pet food, detergent, etc.) therewithin. In addition to such beneficial characteristics, the improved dual container system of the present invention provides a unique horizontal support for a smaller container in order to prevent problems associated with inadvertent slippage thereof as described above.

In accordance with a preferred embodiment of the present invention, the dual container system features a first container (i.e., a smaller container) having a first container body. The dual container system of the present invention features a second container (i.e., a larger container) which has a second container body. The second container defines a second body height, a second body wall thickness and two opposing second body sides.

In the preferred embodiment, the second container body is fabricated from a plastic material and has a generally cylindrical configuration. The second container body preferably has proximal and distal parting lines. The proximal and distal parting lines are formed on respective ones of the opposing second body sides and are extended along the second body height.

Also provided in the preferred embodiment of the present invention, is a body recess formed within the second container and which is adapted to releasably engage the first container body of the first container. More specifically, the body recess is formed on the second container body and is extended at least partially along the second body height. The body recess defines at least one recess bottom corner having a recess bottom corner wall thickness. In addition, the body recess defines at least one vertical edge formed at an intersection of the second body side with the body recess.

In the preferred embodiment, there are two recess bottom corners and two vertical edges. The thickness of each of the recess bottom corner walls and vertical edges is preferably at least substantially similar to the thickness of the second container body. Preferably, each of the recess bottom corner wall thicknesses and vertical edges are at least identical to, if not greater than, the second body wall thickness of the second container body. These specified bottom corner wall thicknesses and vertical edges of the body recess allow the second container to withstand a single impact or repeated impacts caused thereupon. The second container body wall thickness and the recess bottom corner wall thicknesses as well as the thickness of the vertical edges preferably ranges between about 0.01 inches and 0.20 inches. In addition, the body recesses are preferably angularly offset by approximately 90° from each of the body parting lines.

In accordance with the preferred embodiment of the present invention, the body recess is sized and configured to accommodate only a portion of the first container body. In this regard, a remaining portion of the first container body may extend upwardly outside of the body recess and thereby protrude beyond the second container body. However, it is contemplated that the body recess is sized and configured to completely contain the first container body.

The second container body preferably includes at least one and, more preferably, a plurality of lateral body extensions. Each of the lateral body extensions is extended generally perpendicularly outwardly relative to the second body height. In addition, each of the lateral body extensions is extended partially into the body recess. By configuring the second container and the body recess in this manner, the lateral body extensions may effectively retain the first container body within the body recess.

In the present invention, the second container body may include a handle which extends along the body height. In the preferred embodiment, the handle is substantially aligned with the proximal parting line and is disposed substantially opposite from the distal parting line. More preferably, the handle is angularly offset approximately 90° from the body recess.

The second container body may also include a supporting shelf within the body recess. In the preferred embodiment, the supporting shelf is extended generally perpendicularly relative to the second body height. Furthermore, the supporting shelf is extended within the body recess adjacent to the at least one recess bottom corner. In this regard, the supporting shelf provides a bottom for the body recess wherein the supporting shelf extends across the body recess from one recess bottom corner to the opposing one of the recess bottom corners. By configuring the second container in this manner, the supporting shelf can effectively support the first container body thereupon.

Regarding the method of manufacture, in accordance with a primary (i.e., best method) preferred embodiment of the process for manufacturing the second container of the present invention, there is provided a method of manufacturing the container system using an injection control unit. The injection control unit may include an injection unit body and an injection control member which are operative in combination with one another to form an expandable molding balloon from preform material in order to form the second container of the present invention. In its broadest method, the present method includes the step of forming a first container of the container system.

In addition, the method of the present invention includes the step of forming the second container of the container system. As was earlier mentioned, the second container has two opposing parting lines and a second body wall thickness. In forming the second container, the preform material is injected into the injection control unit. More specifically, the injection control unit is selectively operated in order to provide an openable/closable injection gap which is formed between the injection unit body and the injection control member. Preform material, such as plastic, is injected into the injection control unit and passes through the injection gap when the injection gap is opened.

Thereafter, the injection control member of the injection control unit is strategically moved relative to the injection unit body in order to regulate flow of the preform material through the injection gap in order to create the expandable molding balloon. The injection unit body and/or the injection control member may each be formed with a generally oval configuration in order to direct a greater flow of preform material through the injection gap so as to facilitate the creation of molding bands and/or vertical thickened portions within the expandable molding balloon. As will be described in greater detail below, the molding bands provide areas of thickened portions within the recess bottom corners of the body recess. Likewise, the vertical thickened portions provide areas of thicker sections within the vertical edges of the body recess.

In this regard, by moving the injection control unit with respect to the injection unit body, the flow of preform material through the injection gap can create molding bands which are areas of thickened preform material so as to facilitate formation of the recess bottom corners having greater wall thickness as compared to other areas of the second container body.

Also, by including a generally oval configuration in either one of the injection unit body and the injection control member, a greater amount of preform material may be provided to the expandable molding balloon so as to create the vertical thickened portions. In addition, the generally oval configuration of either the injection unit body and/or the injection control member can facilitate formation of the recess bottom corner having a greater wall thickness.

For strategic movement of the injection control member, the injection control unit is first configured or programmed to account for a plurality of points wherein the second body wall thickness may undesirably change (i.e., become thinner). The injection control member may then moved upward or downward relative to the injection unit body based on such preprogramming of the points therein. Such programming and resultant movement of the injection control member relative to the injection unit body regulates the width of the injection gap in order to control the flow of the preform material in the creation of the expandable molding balloon.

The method of the present invention further includes a secondary preferred step (i.e., second best method) wherein the at least one recess bottom corner of the body recess is thickened in order to ensure that the recess bottom corner wall thickness is substantially similar to or at least identical to, if not greater than, the second body wall thickness.

More particularly, it is contemplated that the at least one injection scallop may formed on either the injection control member or the injection unit body. However, it is also contemplated that the injection scallop may be formed on both the injection control member and the injection unit body. By providing the injection scallop, the flow of the preform material to localized areas defined by the injection scallop results in the formation of the vertical thickened portions of the expandable molding balloon.

In addition, at the intersection of the bottom of the body recess with the walls of the body recess (i.e., at the bottom recess corners) the inclusion of the injection scallop provides additional preform material to the recess bottom corners. However, by providing the at least one injection scallop, the flow of preform material to selected portions of the expandable molding balloon may be increased, particularly in the areas of the vertical edges. Due to such thickening of the recess bottom corners, as well as to thickening of the vertical edges due to the vertical thickened portions in the expandable molding balloon, the second container of the present invention may withstand the single impact or repeated impacts undesirably caused thereupon.

After forming the expandable molding balloon, the perform material thereof is then expanded in order to form the second container while simultaneously forming the body recess. Advantageously, due to the inclusion of several features including the generally oval configuration of the injection control member and injection unit body as well as the optional inclusion of the injection scallop in addition to the selective control of the injection gap by moving the injection unit body with respect to the injection control member, the vertical thickened portions and the recess bottom corners may have increased wall thickness so as to withstand repeated impacts.

BRIEF DESCRIPTION OF THE DRAWINGS

These as well as other features of the present invention will become more apparent upon reference to the drawings wherein:

FIG. 1 is a side view of a dual container system constructed in accordance with a preferred embodiment of the present invention and illustrating its second container which is adapted to accommodate and engage its first container via a body recess formed thereon and further illustrating a pair or vertical edges formed at an intersection of the second container with the body recess;

FIG. 2 is a top plan view of the dual container system shown in FIG. 1 and illustrating the body recess of its second container which is angularly offset about 90° from a handle and body parting lines thereof;

FIG. 3 is a bottom plan view of the dual container system shown in FIG. 1 and illustrating a supporting shelf which is formed and extended within the body recess of its second container for supporting its first container thereupon;

FIG. 4 is a partial cross-sectional view of the second container shown in FIG. 1 to illustrate one uniform wall thickness between its second container body and recess bottom corners;

FIG. 5 is a perspective view of an injection control unit of a blow molding machine which is utilized for manufacturing the present dual container system of FIG. 1;

FIG. 6 is a top plan view of the injection control unit shown in FIG. 5 and illustrating its injection control member which provides two injection scallops designated for forming vertical thickened portions for vertical edges of FIG. 1;

FIG. 7 is a cross-sectional view of the injection control unit shown in FIG. 5 and illustrating its injection control member which is sized and configured for strategic movement with respect to an injection unit body so as to regulate material flow to create an expandable molding balloon;

FIG. 8 is a cross-sectional view of the expandable molding balloon shown in FIG. 7 to illustrate vertical thickened portions formed by thicker material flow resulting from the two injection scallops of FIG. 6 or 11;

FIG. 9 is a flow diagram which depicts the manufacturing steps in forming the second container of FIG. 1;

FIG. 10 is a perspective view of the injection control unit comprising the injection control member and the injection unit body and further illustrating the two injection scallops formed on an interior edge of the injection unit body; and

FIG. 11 is a top plan view of the injection unit body shown in FIG. 10 and illustrating the generally oval configuration of the injection unit body.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and not for purposes of limiting the same, FIG. 1 illustrates a dual container system 10 constructed in accordance with a preferred embodiment of the present invention. Similar to its prior art counterparts, the dual container system 10 of the present invention is configured to offer the convenience and freedom of product mobility by providing an overall system in which a first container 12 (i.e. smaller container) can be engaged and disengaged from a second container 14 (i.e., larger container). However, unlike its prior art counterparts, the present dual container system 10 possesses a minimum uniform wall thickness throughout the entirety of its body so as to be impact-resistant and further provides a unique horizontal support for accommodating the first container 12 when it engages the second container 14. These features will be better explained shortly below.

The first and second containers 12, 14 are manufactured and utilized for accommodating and containing various products (e.g., shampoo, body wash, candles, toys, pet food, detergent, etc.) therewithin. In this regard, the first and second containers 12, 14 may be formed to have a variety of shapes, configurations, geometries and textures which are sufficient for accommodating and containing such products. Although the containers 12, 14 comprising the dual container system 10 of the present invention may be fabricated from any material that can provide rigidity or semi-rigidity, it is preferred that they are made from a plastic material such as high-density polyethylene plastic.

In a preferred embodiment, the second container 14 has a second container body 18 that is fabricated from extrusion blow-moldable polyvinylchloride (PVC) material. In another preferred embodiment, the second container body 18 is fabricated from polycarbonate material. In another preferred embodiment, the second container body 18 is fabricated from modified polyethylene terephthalate (“modified PET”) which may be formulated as an extrusion blow-moldable copolyester material. In another preferred embodiment, the second container body 18 is fabricated from clarified polypropylene.

Advantageously, the use of extrusion blow-moldable PVC as a fabricating material results in an improved level of clarity for the second container body 18 of the second container 14. Furthermore, it was discovered that fabricating the second container 14 from extrusion blow-moldable PVC results in improved flexibility and resistance to cracking while retaining clarity over time as compared to other polymers. In addition, fabricating the second container body 18 of the second container 14 from extrusion blow-moldable PVC results in improved impact resistance for the second container 14.

An extrusion blow-moldable copolyester material that may be used in fabricating the second container body 18 is Eastar Copolyester EB062, commercially available from the Eastman Chemical Co. and described in U.S. Pat. No. 4,983,711 issued to Sublett, et al. on Jan. 8, 1991 and entitled COPOLYESTERS AND ARTICLES EXTRUSION BLOW-MOLDED THEREFROM, herein incorporated by reference in its entirety.

The use of extrusion blow-moldable PVC, clarified polypropylene, modified PET, and polycarbonate facilitates the formation of relatively large articles such as the second container body 18 that is included with the container system 10 of the present invention. Fabricating the second container 14 from clarified polypropylene, modified PET, and polycarbonate provides the second container body 18 with improved aesthetics such as high clarity. Furthermore, it has been discovered that fabricating the second container body 18 from extrusion blow-moldable PVC, modified PET, and polycarbonate results in a relatively glossy surface finish to outer surfaces of the second container body 18.

In addition, it was discovered that fabricating the second container body 18 from extrusion blow-moldable PVC as well as extrusion blow-moldable copolyester material such as Eastar Copolyester EB062 advantageously results in less shrinkage of the second container body 18 than when the second container body 18 is fabricated using polyethylene. The ability to limit such shrinkage prevents the formation of depressions in the wall of the containers as it cures, which, in turn, creates fitment problems of the first container 12 within the second container 14. In this regard, the use of extrusion blow-moldable PVC, Eastar Copolyester EB062, clarified polypropylene or polycarbonate allows an observer to accurately discern the visual attributes of product contained within the second container 14 in a manner that may be more visually appealing to consumers.

It has been determined that fabricating the second container body 18 from extrusion blow-moldable PVC, clarified polypropylene, polycarbonate or modified PET such as extrusion blow moldable copolyester material (e.g., Eastar Copolyester EB062) results in improved flow characteristics of the material during the molding process. Such improved flow characteristics of the material result in a more uniform thickness throughout the second container body 18. As may be appreciated, such uniform thickness results in improved strength properties of the second container body 18 as was evidenced during drop testing of the second container 14.

Furthermore, such uniform thickness results in the proper formation of certain features or portions of the second container body 18 that would otherwise be formed without sufficient thickness. In extreme cases using certain plastics having unfavorable flow characteristics, it was discovered that certain features of the second container body 18 were not materialized in the finished product (i.e., were not formed with the finished product). However, by using extrusion blow-moldable PVC, modified PET, polycarbonate and clarified polypropylene materials which possess favorable flow characteristics, the features of the second container body 18 that are located at the outer extremities (e.g., the handle 44) advantageously receive sufficient material to allow complete forming thereof.

Each of the above-mentioned materials (e.g., modified PET, extrusion blow-moldable PVC, extrusion blow-moldable copolyester material, Eastar Copolyester EB062 material, polycarbonate material, and clarified polypropylene material) provide the second container body 18 with favorable mechanical properties such that the container system 10 of the present invention is capable of withstanding repetitive impacts such as may occur when the container system 10 is repeatedly dropped or mishandled during shipment, storage and everyday use. For example, Applicant has unexpectedly discovered that fabricating the second container body 18 from modified PET allowed the second container body 18 to survive a drop test wherein the second container body 18 was dropped from a height of about six feet with substantially no damage thereto despite the fact that the second container body 18 was only expected to survive a drop test of only three feet.

As was also earlier mentioned, the second container body 18 may be fabricated from polycarbonate material such as that which is described in U.S. Pat. No. 4,034,016 issued to Baron, et al. on Jul. 5, 1977 and entitled TERNARY POLYBLENDS PREPARED FROM POLYBUTYLENE TEREPHTHALATES, POLYURETHANES AND AROMATIC POLYCARBONATES, herein incorporated by reference in its entirety. It has been determined that although polycarbonate similar to that disclosed in U.S. Pat. No. 4,034,016 may possess a slightly yellowish tint, the addition of blue tint partially offsets the normally yellow tint and improves the aesthetics of the second container body 18.

The second container body 18 may further be formed of extrusion blow molded clarified polypropylene such as that which is commercially available from Milliken & Company of Spartanburg, S.C. Such clarified polypropylene has improved clarity as compared to traditional polypropylene due to the addition of nucleating or clarifying agents in the polypropylene. Although clarified polypropylene does not result in the same level of clarity as that which is attainable when the second container body 18 is fabricated from extrusion blow-moldable PVC, polycarbonate or modified PET, it is believed that clarified polypropylene is a suitable material for fabricating the second container body 18 due to its favorable strength properties as well as its improved clarity as compared to polyethylene.

Referring more particularly to FIGS. 1-3, as the first and second containers 12, 14 may be any general desired shape, it is understood that the containers 12, 14 as depicted are symbolic in nature. As discussed above, it is the inventive concepts of providing one impact-resistant uniform thickness and horizontal support that should be appreciated. However, the first and second containers 12, 14 are each depicted as having a generally cylindrical configuration of differing sizes. In other words, they are each shaped like a bottle container, with the second container 14 being larger in size than the first container 12. Of course, such sizing is inevitable as the second container 14 is provided to engage and support the first container 12.

Referring now back to FIG. 1, the first container 12 of the present dual container system 10 has a first container body 16. Likewise, the second container 14 has a second container body 18. Although the following pages are devoted mostly to describing the unique specifications of the second container body 18 as it is the second container body 18 which is often subjected to tear and rupture, one of ordinary skill in the art will recognize that the first container body 16 may be manufactured to closely resemble and adhere to the specifications of the second container body 18. Alternatively, however, the first container body 16 may be made in accordance with conventional knowledge of manufacture and does not absolutely have to follow the unique specifications of the second container body 18.

Referring now to FIGS. 1-4, the second container body 18 defines a second body height 20, a second body wall thickness 22 and two opposing second body sides 24. The second container body 18 also has a proximal parting line 26 and a distal parting line 28. More specifically, the proximal and distal parting lines 26, 28 are defined on respective ones of the opposing second body sides 24 and are extended along the second body height 20 of the second container body 18.

Importantly, the second container body 18 forms a body recess 30 which is adapted to releasably engage the first container body 16 of the first container 12. In particular, the body recess 30 is formed on the second container body 18 and is extended along the second body height 20 thereof. The body recess 30 defines a recess top portion 32 which is designed to expose the first container body 16 therethrough when it engages the body recess 30. Optionally, the second container body 18 may have a finger-indent 34 adjacent the recess top portion 32 for facilitating the detachment of the first container body 16 from the body recess 30 (best shown in FIG. 2).

Opposite from the recess top portion 32 along the second body height 20 is defined a recess bottom portion 36 of the body recess 30. The recess bottom portion 36 includes two recess bottom corners 38 each defining a recess bottom corner wall thickness 40, the significance of which will be described shortly (best shown in FIGS. 1 and 3). In addition, the second container includes vertical edges at the recess which may have increased wall thicknesses due to the addition of a pair of injection scallops formed on an injection unit body and/or on an injection control member of a blow molding machine used to fabricate the second container, as will be described in greater detail below.

As illustrated in FIG. 4, each of the recess bottom corner wall thicknesses 40 are at least substantially similar to or identically thickened to the second body wall thickness 22 of the second container body 18. These specified bottom corner wall thicknesses 40 of the body recess 30 allow them to withstand a single impact or repeated impacts caused thereupon, at least to the same degree or extent as the rest of the second container body 18. As this is one of the objectives of the present invention, it is contemplated herein that the recess bottom corner wall thicknesses 40 may be greater than the second body wall thickness 22 of the second container body 18. In the preferred embodiment of the present invention, the second body wall thickness 22 and the recess bottom corner wall thicknesses 40 preferably range from about 0.0005 inches to about 0.5 inches, and more preferably from about 0.01 inches to about 0.2 inches.

Referring now back to FIGS. 1-3, the body recess 30 is preferably formed in an angular offset from the proximal and distal parting lines 26, 28 of the second container body 18. In particular, the preferred angular offsetting of the body recess is approximately 90° from each of the body parting lines 26, 28. This specified angular offsetting of the body recess 30 provides a sufficient distance from each of the body parting lines 26, 28 where the two body halves come together to form the second container body 18. This allows the body recess 30 to better remain intact, and hence maintaining the structural integrity of the wall thicknesses 22, 40 throughout the second container 14 after being impacted singly or multiply by an undesired factor in its external environment.

Further advantage lies in that such positioning allows the plastic material to stretch properly when it is blown and prevents the general corners/edges of the second container body 18 from becoming too thin after being molded. Simply put, this specified positioning is the most efficient accommodation of the body recess 30 and ensures that the second container 14 is fabricated optimally. It is foreseeable that a second or additional body recess may be optionally formed on the second container body 18 substantially opposite from the already provided body recess 30.

The body recess 30 formed along the second container body 18 is sized and configured to engage and accommodate only a selected portion of the first container body 16 therewithin. In this respect, a remaining portion of the first container body 16 that is not engaged and accommodated becomes exposed outside the body recess 30 and protrudes outward beyond the second container body 18. However, it should be noted herein that the body recess 30 may be optionally deepened further to accommodate the first container body 16 completely therewithin.

Although various methods and devices may be used for engaging and accommodating the first container body 16, a plurality of lateral body extensions 42 are preferably provided by the second container body 18 to be used for this purpose. More specifically, each of the lateral body extensions 42 are extended generally perpendicular to the second body height 20 and partially into the body recess 30. By such configuration, the lateral body protrusions 42 can capture and retain the accommodated portion of the first container body 16 within the body recess 30. In other words, the first container 12 may be snapped into the body recess 30 wherein each of the lateral body protrusions 42 would operate to apply either a frictional or compressive force upon the first container body 16 for retention.

FIGS. 1 and 2 show a handle 44 which is extended along the second body height 20 of the second container body 18. Preferably, this handle 44 is substantially aligned with the proximal parting line 26 and is disposed substantially opposite from the distal parting line 28. Further preferably, the handle 44 of the second container body 18 is angularly offset approximately 90° from the body recess 30 for the reasons related to providing better structural integrity that can withstand unwanted external impacts. Moreover, this specific positioning of the handle 44 allows the plastic material to stretch properly when it is blown and is the most efficient manner of accommodating the handle 44.

Referring particularly to FIGS. 1 and 3, the second container body 18 preferably includes a supporting shelf 46. In the preferred embodiment of the present invention, the supporting shelf 46 is extended generally perpendicular to the second body height 20 of the second container body 18. Further to such requisite specification, the supporting shelf 46 is extended around and within the body recess 30 adjacent to the recess bottom corners 38 thereof. By providing such specially formed shelf 46, the accommodated portion of the first container body 16 may be supported upon the supporting shelf 46 of the second container body 18. This would clearly prevent any inadvertent or unintentional slipping of the first container body 16 from underneath the body recess 30 of the second container body 18.

With the structures of the present dual container system 10 now defined, its method of manufacture can be clearly described in view of FIGS. 5-9 provided herein. In order to manufacture the dual container system 10 as specified above, the first container 12 of the container system 10 is first formed, preferably through a plastic blow molding process. As stated above, the first container 12 may be manufactured in the similar manner as the second container 14 as will be described shortly below, or manufactured in accordance with conventional modes of plastic blow molding process. This is because it is the second container 14 which is the component of the overall dual container system 10 that is often subjected to tear and rupture during its shipment, storage or handling.

Next is the step of forming the second container 14 of the container system 10, preferably also through a plastic blow molding process. More particularly, to form the second container 14, a preform material 58 is first injected into the injection control unit 48 of a blow molding machine (step 100). Various customized blow molding machines may be used for this purpose. One exemplary machine which may be used is the blow molding machine model # BW 6000 DE from Uniloy Milacron, Inc. of Ohio, U.S.A. More specifically, the blow molding machine comprises the customized injection control unit 48. This customized injection control unit 48 is formed essentially of an injection unit body 50, an injection control member 52 which are used to form an expandable molding balloon 54 which is extended through the injection unit body 50 (best shown in FIG. 7).

The customized version of the injection control unit 48 is adapted to provide an openable/closeable injection gap 56 between its injection unit body 50 and the injection control member 52. The preform material 58 is injected into the injection control unit 48 through the injection gap 56 when it is opened. Thereafter, the injection control member 52 of the injection control unit 48 is strategically moved up and down with respect to the injection unit body 50 to open, close and/or vary the size of the injection gap 56 (step 102).

This is to regulate the flow of the preform material 58 through the injection gap 56 and to create the expandable molding balloon 54. In the preferred embodiment of the present invention, the injection control member 52 has a generally oval configuration and creates the injection gap 56 around its oval periphery. The oval shape in itself will provide a greater flow in strategic areas of the molding balloon 54, thus thickening the molding balloon 54 in those areas vertically as is best shown in FIG. 8.

Referring now to FIGS. 10 and 11, in another preferred embodiment of the invention, the injection unit body 50 defines an interior surface 68 with an interior edge 70. The interior surface 68 may have a generally oval or circular configuration in one of the preferred embodiments. The oval shape of the interior surface 68, in combination with a generally circular shape of the injection control member 52, will provide a greater flow of material through the injection gap 56 which, in turn, results in greater flow to strategic areas of the expandable molding balloon 54, thus thickening the molding balloon 54 in those areas vertically. In this regard, it is contemplated that the injection unit body 50 has the generally oval configuration while the injection control member 52 has a generally circular shape. Alternatively, however, the injection control member 52 may have the generally oval shape while the injection unit body 50 may have a generally circular configuration, as described above.

The interior surface 68 of the injection unit body 50 also defines an interior edge 70 on a side of the injection unit body 50. At least one and preferably two injection mold scallops 60 may be provided on the interior edge 70 of the injection unit body 50 in order to further provide a greater flow in strategic areas of the molding balloon 54, as shown in FIG. 8, in order to generate the vertical thickened portions 66.

In this regard, it is contemplated that the interior surface 68 of the injection unit body 50 may be provided with a generally circular shape, as opposed to the generally oval shape, and that the at least one scallop 60 may either be included or omitted from the interior edge 70, depending upon the desired molding characteristics and molding material that is used. It should be noted that the injection mold scallops 60 may be included in either an ovally-shaped or a circularly-shaped configuration of the injection control member 52 and/or of the injection unit body 50. The scallops 60 and the oval configuration may both generate generally thickened portions as shown in FIG. 8.

Although the oval configuration of the injection unit body 50 and/or of the injection control member 52 is preferred, it should be noted herein that other types of configurations are also workable with the methodology of the present invention. For instance, the injection unit body 50 and/or the injection control member 52 may be more or less rounded. In this manner, when the injection control member 52 is brought to the injection unit body 50, they collectively define a slightly differently-shaped injection gap 56 than the one provided by the oval configuration. This may affect the flow to the molding balloon 54 but nonetheless provides the desired flow to strategic areas of the molding balloon 54. In addition to such alternative shapes of the injection unit body 50 and/or of the injection control member 52, it is also recognized herein that the injection control member 52 may be shifted toward one particular side of the injection unit body 50 so as to define different variations of the injection gap 56 which will produce the desired flow.

To conduct such strategic movement of the injection control member 52, the blow molding machine and its injection control unit 48 is first set or programmed to account for a plurality of points where the second body wall thickness 22 of the second container body 18 could undesirably change (step 104), possibly to extreme stretching of the molding balloon 54 due to the shape of the body recess 30. In order to exemplify this concept, the blow molding machine is programmed in approximately 100 points where thicknesses of the second container body 18 may change, and to account for such undesirable thickness changes. Based upon this presetting or preprogramming of the blow molding machine, the injection control member 52 is then moved selectively and strategically in upward and downward directions relative to the injection unit body 50 (step 102). This selectively accesses the injection gap 56 which is provided between the injection control member 52 and the injection unit body 50 in order to control the flow of the preform material 58 to the expandable molding balloon 54 (step 106).

The manufacturing method further includes the step of selectively regulating the flow of the preform material through the injection gap 56 to create at least one molding band 59 in the expandable molding balloon 54 for thickening at least one recess bottom corner 38 of the body recess 30 to have a recess bottom corner wall thickness 40 which is at least identical to the second body wall thickness 22 (step 106). In this process, the body recess 30 and, more particularly, the recess bottom corners 38, are at least substantially similar to or identically thickened to the second container body 18 thickness in order to increase its overall structural integrity. As was mentioned above, the expandable molding balloon 54 is molded into the second container 14 to create the body recess in the second container 14. The body recess is adapted to releasably engage the first container 12.

In order to derive such recess bottom corners 38, the flow of the preform materials 58, such as the PVC material, designated for forming the recess bottom corners 38 may be increased due to the addition of the molding bands 59 in the expandable molding balloon 54 which are represented as the thickened areas in FIG. 7. Such thickened areas are formed by increasing the gap 56 such that a greater amount of preform material 58 flows therethrough and which causes a local increase in the thickness of the expandable molding balloon 54. The molding bands 59 are generally formed in a circumferential or circular orientation.

Such molding bands 59 are also preferably strategically located at the point where the recess bottom corners 38 of the second container 14 will be formed. The flow of the preform materials 58 designated for forming the recess bottom corners 38 may be increased at the molding bands 59 due primarily by moving the injection control member 52 in and out relative to the injection unit body 50 to locally increase the injection gap 56. The flow of the preform material 58 may also be secondarily increased due to the ovality formed at the outer periphery 62 of the injection control member 52 and/or due to the ovality formed at the interior edge of the injection unit body 50 or a combination of ovality formed in both of the outer periphery 62 and the interior edge 70.

In addition, vertical thickened portions 66 of the second container 14 may be formed as shown in FIG. 8. Such vertical thickened portions 66 are preferably strategically located so as to coincide at an intersection of the body recess 30 and the second container body 18 sides as shown in FIGS. 1-3. Each one of the intersections is vertically oriented as shown in FIG. 1 and forms a vertical edge 64 or corner that is preferably radiused. The vertical thickened portions 66 are formed primarily due to the oval configuration formed on the injection unit body 50 and/or on the injection control member 52. The vertical thickened portions 66 are formed secondarily due to the inclusion of the injection scallops 60 in the injection unit body 50 and/or in the injection control member 52.

Preferably, there are two of the injection scallops 60 formed on the injection unit body 50 and/or on the injection control member 52, each being designated for forming the vertical edge of the body recess 30. By providing these injection scallops 60, the flow of the preform material 58 to selected portions of the expandable molding balloon 54 which are adapted to form the vertical thickened portions 66 may be increased. As such, the vertical thickened portions 66 are preferably thickened to at least a thickness that is identical to the second body wall thickness 22 of the second container 14. The body recess 30 may angularly offset approximately 90° from each of the parting lines 26, 28.

Also in the process, the handle 44 may be extended upon the second container 14. As noted above, the handle 44 is disposed in substantial alignment with one of the parting lines 26 and is further disposed substantially opposite from the other parting line 28. The handle 44 should also be formed to be angularly offset approximately 90° from the body recess 30.

Further in the process, the supporting shelf 46 is also provided for supporting the first container 12 thereupon. As indicated above, the supporting shelf 46 is preferably extended within the body recess 30 adjacent to its recess bottom corners 38.

Additional modifications and improvements of the present invention may also be apparent to those of ordinary skill in the art. Thus, the particular combination of parts described and illustrated herein is intended to represent only certain embodiments of the present invention, and is not intended to serve as limitations of alternative devices within the spirit and scope of the invention. 

1. A container system adapted to withstand an impact, the container system comprising: a first container having a first container body; and a second container, comprising: a second container body having a second body height and a second body wall thickness; and a body recess adapted to releasably engage the first container body of the first container, the body recess being formed on the second container body and extending along the second body height, the body recess defining at least one recess bottom corner having a recess bottom corner wall thickness which is at least identical to the second body wall thickness of the second container body, wherein the specified bottom corner wall thickness of the body recess allows the second container to withstand the impact; wherein the second container body is fabricated from polyvinylchloride.
 2. The container system of claim 1 wherein the intersection of the body recess with the second container forms at least one vertical edge having a thickness that is at least identical to the second container body wall thickness.
 3. The container system of claim 1 wherein the second container body has a generally cylindrical configuration.
 4. The container system of claim 1 wherein the second container body has two opposing second body sides, the second container body further having proximal and distal parting lines formed on respective ones of the opposing second body sides and extending along the second body height.
 5. The container system of claim 4 wherein the body recess is angularly offset approximately 90° from each of the parting lines.
 6. The container system of claim 4 wherein the second container body comprises a handle extending along the body height, the handle being substantially aligned with the proximal parting line and being disposed substantially opposite from the distal parting line, the handle further being angularly offset approximately 90° from the body recess.
 7. The container system of claim 1 wherein the body recess is sized and configured to accommodate only a portion of the first container body such that a remaining portion of the first container body becomes exposed outside the body recess and protrudes outward beyond the second container body.
 8. The container system of claim 7 wherein the second container body includes a plurality of lateral body extensions, each of the lateral body extensions being extended generally perpendicular to the second body height, each of the lateral body extensions further being extended partially into the body recess for capturing and retaining the portion of the first container body within the body recess.
 9. The container system of claim 7 wherein the second container body includes a supporting shelf, the supporting shelf being extended generally perpendicular to the second body height, the supporting shelf further being extended within the body recess adjacent to the at least one recess bottom corner for supporting the portion of the first container body thereupon.
 10. The container system of claim 1 wherein the at least one recess bottom corner comprises two recess bottom corners.
 11. The container system of claim 1 wherein the second body wall thickness and the recess bottom corner wall thickness range between about 0.01 inches and 0.2 inches.
 12. A method of manufacturing a container system with an injection control unit having an injection unit body, the method comprising the steps of: a) forming a first container of the container system; and b) forming a second container of the container system, the second container having two opposing parting lines and a second body wall thickness, the second container having a body recess, comprising the steps of: 1) injecting a preform material into the injection control unit; 2) strategically moving an injection control member of the injection control unit with respect to the injection unit body to regulate a flow of the preform material for creating an expandable molding balloon, the injection unit body having an interior edge with a generally oval configuration; 3) selectively regulating the flow of the preform material to create at least one molding band in the expandable molding balloon for thickening at least one recess bottom corner of the body recess to have a recess bottom corner wall thickness which is at least identical to the second body wall thickness; 4) molding the expandable molding balloon into the second container to create the body recess in the second container, the body recess being adapted to releasably engage the first container; and 5) withstanding an impact upon the second container due to the recess bottom corner wall thickness.
 13. The method of claim 12 wherein the preform material in step b1) is a plastic material.
 14. The method of claim 12 wherein the preform material in step b1) is extrusion blow-moldable polyvinylchloride.
 15. The method of claim 12 wherein step b1) comprises: i) defining an openable/closeable injection gap between the injection unit body and the injection control member; and ii) injecting the preform material into the injection control unit through the injection gap when the gap is opened.
 16. The method of claim 12 wherein step b2) comprises: i) setting the injection control unit for strategically moving the injection control member so as to account for a plurality of points where the second body wall thickness undesirably changes; ii) moving the injection control member in upward and downward directions relative to the injection unit body based upon the presetting thereof; and iii) selectively accessing an injection gap provided between the injection control member and the injection unit body to control the flow of the preform material to the expandable molding balloon.
 17. The method of claim 12 wherein step b4) comprises: i) offsetting the body recess approximately 90° from each of the parting lines.
 18. The method of claim 12 wherein step b4) comprises: i) extending the handle upon the second container in substantial alignment with one of the parting lines and substantially opposite from the remaining parting line; and ii) offsetting the handle approximately 90° from the body recess.
 19. The method of claim 12 wherein step b4) comprises: i) extending a supporting shelf within the body recess adjacent to the at least one recess bottom corner for supporting the first container thereupon.
 20. The method of claim 12 wherein an intersection of the body recess with the second container forms at least one vertical edge and wherein step b3) comprises: i) defining an interior edge of the injection unit body; ii) defining at least one injection scallop formed on the interior edge, the at least one injection scallop being configured to form a vertical thickened portion of the expandable molding balloon; and iii) increasing the flow of the preform material through the at least one injection scallop to derive the at least one vertical thickened portion thickened having a thickness that is at least identical to the second body for the vertical edge.
 21. The method of claim 12 wherein the injection control member has a generally oval configuration. 